Pressure intensifiers have long been used to pressurize media to very high pressures. Usually, the pressure intensifier comprises a low-pressure chamber and one or more high-pressure chambers. In the low-pressure chamber a low-pressure piston is displaceably arranged. This low-pressure piston is secured to a high-pressure piston in the respective high-pressure chamber. The low-pressure piston has an area which is larger than the area of the high-pressure pistons.
Upon pressurization of a medium, the medium is supplied through an inlet to the high-pressure chamber. The inlet is closed, whereupon a certain relatively low pressure is supplied to the low-pressure chamber. This usually occurs hydraulically. When the supplied pressure acts on the low-pressure piston, the piston is displaced, causing the high-pressure piston to be displaced inwards in the high-pressure chamber. Since the high-pressure piston has a smaller area than the low-pressure piston, the displacement will result in a certain higher pressure of the medium in the high-pressure chamber. The pressurized medium can thereafter, via an outlet arranged in the high-pressure chamber and via high-pressure conduits, be passed on to an external pressure device, for example a press. With this type of pressure intensifier, pressures up to around 15000 bar may be attained.
One known type of pressure intensifier comprises two high-pressure chambers. These high-pressure chambers are arranged coaxially with the low-pressure chamber, one on each side thereof. Each high-pressure chamber is limited at its outer ends by an end member and exhibits an axially displaceable high-pressure piston which is secured to the low-pressure piston in the low-pressure chamber. When the low pressure is supplied to the low-pressure chamber on one side of the low-pressure piston, the low-pressure piston is displaced in the opposite direction. This leads to generation of the high pressure in that high-pressure chamber which is arranged on that side of the low-pressure piston which is opposite to that where the low pressure is supplied.
By alternately supplying the low pressure to each side of the low-pressure piston, this type of pressure intensifier may be caused to operate as a double-acting pump. When the pistons are in one of their end positions, the first high-pressure chamber is empty and the second high-pressure chamber is filled with non-pressurized medium. When, thereafter, the pistons are displaced towards the other end position, the first high-pressure chamber is filled with non-pressurized medium via its inlet. At the same time, during the first part of the displacement, the medium in the second high-pressure chamber is pressurized. During the remaining displacement, when the high pressure has been achieved, the pressurized medium is pressed out of the second high-pressure chamber and via its outlet and a high-pressure conduit to the external pressure device where the same high pressure prevails. When the pistons are moved back to their first end position, the second high-pressure chamber is filled with non-pressurized medium while at the same time the medium in the first high-pressure chamber is pressurized and is pressed out into the external unit.